


and breathing is wishing

by jillyfae



Series: when more than was lost has been found [1]
Category: Shadowhunters (TV)
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Merpeople, Communication, Curses, Extenuating Circumstances!, Lack of Communication, M/M, Magic, MerMay, Romance
Language: English
Status: Completed
Published: 2019-05-05
Updated: 2019-05-05
Packaged: 2020-02-26 17:08:15
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,968
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18721354
Author URL: https://archiveofourown.org/users/jillyfae/pseuds/jillyfae
Summary: "Sea curses are strong, and never fade, never will, until the tides themselves cease moving."Magnus isn't entirely sure when he was supposed to notice that apparently his boyfriend was cursed. (Never a boring day, being in love with Alec Lightwood? He supposes that's as much of an answer as he's likely to get.)





	and breathing is wishing

**Author's Note:**

> [tumblr prompt: cuddling while someone’s sick](https://faejilly.tumblr.com/post/184668588278)
> 
>  
> 
> uh, this went somewhere a little sideways, and then kept GROWING, because #MerMay does that to me? Also apparently I am terrible at sick!fic because this is really not that. But still. Mermaids! Everything's better with mermaids. Mermen. Merpeople? ykwim

Magnus is surprised, the first time he’s in Alec’s rooms at the Institute, to discover he has a private bathroom with an actual tub. Not only that, it’s clearly a custom tub, deep and long enough to fit all 6′3″ of Alec’s impressive height without overflowing around his (equally impressive) shoulders.

He’s also got three different types of bath salts lined up on the ledge against the wall, none of them scented with much of anything, in Magnus’ opinion, but _still._ They’re _there_.

He stands and blinks for a moment, then spins right around to find Alec and ask if he’d like to join him for a _bath._

They haven’t christened Alec’s suite yet, might as well start with the bathroom. He’s pretty sure Alec will enjoy that plan.

* * *

Alec has stretch-marks on his hips and thighs; not surprising, considering the probability of teenage growth-spurts, but they’re heavy enough Magnus can feel them beneath his fingertips when he runs his hands down Alec’s legs, and sensitive enough Alec’s breath catches every single time he does it.

They’re thickest on the inside of his thighs, so every time Magnus might manage to start to wonder about them, about the way Alec’s back twists, pushing him into Magnus’ touch even as he looks like he wants to pull away, Magnus gets distracted by the way Alec’s eyes close, lashes heavy against his cheeks, the lift of Alec’s hips and the heat beneath his skin.

They both enjoy what always happens next.

* * *

Magnus likes the tub, and never really stops to think about it. Alec likes baths. And showers. Whenever he is particularly stressed, whenever the current crisis has finally broken, or paused enough that they can risk a break, Alec will stand in the shower ‘til the water’s tepid, and even then it sometimes takes two or three tries to pull him free and make him eat dinner and stagger off to bed.

Alec likes rain, even the cold sharp-edged storms they get in the fall. He never seems to mind water dripping down his collar. He tilts his head back and blinks into sudden summer showers, and has a ridiculous collection of tides and storms and waterfall pictures for wallpaper on his screens in his office, and occasionally he’ll let his fingertips rest gently on the images before he puts his work away.

Alec likes taking Madzie to the aquarium _every single time she asks,_ and seems to enjoy it as much as she does _every single time._ (Magnus and Catarina no longer go with them. There are only so many times Magnus can listen to the same educational dolphin show in his lifetime, and he’s pretty sure he passed it months ago.)

The only stories Jace and Isabelle share of Alec sneaking away from the Institute when they were young involve the beach, even if it was the middle of winter and no one in their right mind would enjoy the breeze off the North Atlantic.

Those are the only stories anyone seems to have of Alec behaving remotely like a child _at all._ His entire rebellion, sneaking away to a beach to watch the sunrise.

Well, until Magnus, at least.

Magnus is Alec’s exception to every rule.

Magnus enjoys that.

* * *

Magnus doesn’t put it together until Alec spends a little too long in the Southwest, helping to coordinate a round-up of baby basilisks who’d been let loose thanks to a truly incompetent breeding ring the High Warlock of Mexico City had discovered. Alec staggers out of his return portal with fever-bright cheeks, the rest of him looking oddly pale for someone who’d presumably been half-cooked in the desert, croaks out the word _bath,_ dropping bits of gear in a trail before he literally collapses into the tub a bare instant after Magnus summoned water to fill it. If he’d been a half a second faster he probably would have broken something from the impact with the porcelain, but he doesn’t seem to care. He sighs, and lets his head fall under the surface, still wearing his undershirt, which shifts around, trying to billow free, then falling back to stick to his skin.

Magnus blinks.

Alec doesn’t lift his head for a very long time.

When he does he just blinks up at Magnus, reaching an arm out and _whining,_ a sound which should not at all be adorable, but undeniably is.

Magnus strips, and helps Alec get his water-logged shirt off, and slides carefully into the water, adjusting until he’s leaning against the back and Alec is curled up on his chest. They don’t talk, Alec slowly relaxing until he’s half asleep, and Magnus carefully slips a warming spell into the water twice before he finishes rotating the conclusions he’s just reached around and around in his head.

He can’t quite make them fit.

Well.

It fits entirely too well, Maryse’s paranoia and the bath salts Magnus has never actually seen Alec _use,_ the way he reacts to water, to the lack of it. The stretch-marks that aren’t _quite_ normal.

But he’d _tell_ Magnus something like that, wouldn’t he? Especially after all the things Magnus has told him, things he’d never thought he could tell anyone…

Alec shifts in Magnus’ arms, turning his head to nuzzle against Magnus’ chest. Not properly awake, but more than he was a minute ago.

“I know something that helps me relax when I feel ill.” Magnus has to hold tight control of himself so he doesn’t tense, so his hands don’t clench, so his voice doesn’t waver. “Would you like me to add some of your bath salts?”

Alec jerks, and Magnus doesn’t think it’s just because he’s startled by Magnus’ voice. He lifts his head and stares at Magnus. His mouth opens, and Magnus can _see_ his throat working, but not a sound comes out.

“Is that a no, _darling?”_ Magnus is not entirely sure if he’s angry or hurt or confused, and he doesn’t think he can stand it. Enough slips through to make that last word more vicious than he’d intended, but he can’t completely regret it when Alec flinches, because if he wasn’t sure before, he is now. Alec _is_ hiding something from him.

He pushes, and Alec lets him, and he pulls himself out of the tub, water splashing everywhere and his eyes burning and he wants to _break_ something, everything.

He’s not quite steady on his feet on the tile when Alec’s hand wraps around his wrist, the grip a shade too tight. Magnus yanks as he turns, trying to free himself, but he can’t _,_ he doesn’t even know if he really wants to, and Alec’s fingers burn into Magnus’ skin. Magnus looks at him; Alec’s mouth is open and his other hand is pressed to his throat and he’s staring, _staring,_ eyes so wide and impossibly dark and…

“Do I smell brine?”

Alec’s whole body sags with something that looks like relief, his hand slips off Magnus’ arm and he manages half a nod before he seems to lock up again.

Despite his best intentions, Magnus lets the pinpricks of curiosity make their way past the ache in his chest, and he ducks down to look Alec right in the eyes, close enough Magnus’ breath makes the drops of water on Alec’s face shiver.

“Sea magic?”

Alec doesn’t move, but there’s something in his _eyes._

“Sea _curse_?”

Alec blinks just once, slow and deliberate.

“You literally _can’t_ say anything right now, can you?”

There’s no answer at all, not even another blink, which is more than answer enough. But Alec does manage to stare sideways towards the row of bath salts, and Magnus’ throat feels too tight to breathe through.

If he’s read Alec’s expression wrong? This could have terrible consequences. Sea curses are strong, and never fade, never will, until the tides themselves cease moving.

But Magnus _trusts_ Alec.

Alec trusts him too, Magnus knows. He _knows._

He should have known.

Magnus swallows the burn in the back of his throat, and carefully flicks his fingers to knock the smallest container of bath salts over, letting them spill into the tub.

Alec’s back arches and he splashes back under water and the flash of magic across Magnus’ senses is blinding, for all it’s not literally visible.

When he can see again, he’s staring at someone who is even less human than most warlocks, and yet clearly still _Alexander._ Magnus reaches out, until his fingertips just brush against the familiar line of Alec’s jaw. His skin feels thicker somehow, cooler, more taut against his bones. His nose and ears are less pronounced, but the cheekbones are the same, and the shape of his eyes, though the pupil is wider and the whites are now a cloudy grey.

And his eyelashes are gone.

“You have no _hair.”_

Alec’s eyes widen, and then his mouth drops open and his shoulders shift and _the gills on the sides of his neck flutter,_ and Magnus tilts his head to watch. There’s the faintest breathy tremble in the air, and very familiar crinkles surrounding Alec’s eyes.

The extra interior eyelid coming half-way in from the sides of his eyes is less familiar, but still lovely, the skin practically opalescent, and so thin as to _almost_ be transparent.

“Are you laughing at me?”

Alec nods this time, exaggerated and emphatic.

“I’m sorry, I have a lot of questions, and maybe that was not the right place to start but you have rather a lot of hair that I’m quite fond of when you’re uh. Human?” Magnus wrinkles his nose. That sounds oddly dismissive of this lovely merman in front of him, as if it’s lesser rather than different, but he’s not sure how else to phrase it. “Not that you aren’t still gorgeous.”

Alec ducks his head as if uncomfortable with the compliment, and Magnus realizes some of his odd inability to see his own beauty is probably because half the time it’s not _human_ beauty at all.

“Can I see?” Magnus asks, gesturing backwards with a flick of his fingers.

Alec lifts his chin, the start of a smile caught in the edges of his still expressive lips, a hint of mischief in his eyes, and he slides backwards in the tub.

He also _lifts his tail_ and _slaps it_ over the edge of the tub, splattering water across Magnus’ face.

Magnus sputters, and Alec’s smile widens, clearly delighted and, if Magnus isn’t mistaken, _relieved_ by Magnus’ reaction _._

Magnus smiles back, and Alec blinks slowly, his two sets of eyelids clearly visible again, and Magnus thinks that, if he could, Alec might very well be blushing. There is something shy in the tilt of his shoulders, in the shifting of his hands.

Which is as good a place as any to start. Magnus looks at his hands. Three fingers instead of four, a longer thumb, webbed and claw-tipped. The webs between his fingers are the same shimmery silver as his eyelids, the claws short and blunt and black. The shape of Alec’s body is different, his shoulders not as broad, his stomach not as trim, the muscles of his torso longer and leaner beneath the shift of scattered scales.

The scales thicken over his hips, _right in line with the stretch-marks,_ and his tail is entirely covered in them, shining silver and matte black stripes, the wide fin at the end silver with black trim.

“You’re so beautiful, Alexander.” Alec smiles again, small and soft and pleased. “May I kiss you?”

Alec’s eyes widen, clearly surprised, but he nods and leans forward, and Magnus moves in. It’s a small kiss, a slight brush of lips, soft and cool, but as always with Alexander, it’s more than enough to make Magnus’ chest warm with joy.

They smile at each other for a lingering moment, no sound in the room except a few more drips of water from their assorted splashings in and out of the tub.

“Do we have to wait until you’ve turned all Nephilim-y again to talk?”

Alec nods again, lifting his chin, his hand resting over the base of his neck in order to show off the line of his throat.

Magnus hums, wondering if his skin tastes different now. He sees that same flutter of gills like Alec’s laughing, and it takes him a moment to realize that Alec was trying to show him something specific.

The lack of an Adam’s Apple. "No larynx?”

Alec lifts a hand and does an up and down tilt, _sort-of._

“Not the right _kind_ of voicebox? Your mouth and tongue are probably the wrong shape too, aren’t they.”

Alec nods this time.

“So you can make noise?”

Alec wobbles his hand again, and ducks his head under the water. His mouth is closed, but he’s clearly doing something because Magnus can feel it through the tub, a hum against his arm where he’s leaning on the edge, and there’s an odd echo in his ears that he can only half hear, that reminds him of whale song only lighter and sweeter. There’s a tug somewhere in the vicinity of his heart, but before Magnus can wonder about it Alec lifts up, shaking his head, a finger pressed to his lips.

Magnus is not entirely sure if that means _only in the water_ or if there’s something dangerous about that tug he’d felt, something like a literal siren’s song. And for all he’d love to spend the next month getting to know merman-Alec, he also really needs some _answers._

“How do we get your voice back?”

Alec points at the towel, then flops gracelessly sideways to unplug the tub’s drain. Magnus snorts something that’s half-a-laugh, grabs a towel and tosses it over Alec’s head, and heads out to the bedroom to find some clothes.

Eventually they’re both dry (with legs) and in pajamas and snuggled up in bed with summoned tea so they neither of them have to leave the room.

“Thank you for figuring it out.” Alec’s tea is tucked right up against his chest so he can inhale the last lingering wafts of steam. His other hand is tangled with Magnus’, his fingers still holding tight as if he can’t yet believe it, as if he can’t stand the idea of ever letting go. “I _hated_ not being able to say anything, I’m so sorry.”

“But there’s no trouble now?” Magnus rubs his thumb against Alec’s knuckle. They’re both speaking quietly, as if even here, alone in the bedroom, it’s too risky for more.

“The Curse only prevents us from talking to anyone who doesn’t already know.”

“Us? Do Jace and Isabelle know?”

Alec, surprisingly, shakes his head. “Jace knows there’s something, I think he can feel something through the bond when I change, but he hasn’t figured it out and I can’t tell him, I can’t even tell him that there’s something I can’t tell him? So he ignores it. It’s possible the Curse influences him a little too, just enough that he can’t manage to really think about it, or ask the right questions.”

Magnus frowns and pushes further back against the headboard so it’s easier to look sideways at Alec’s face. “That’s both nasty and comprehensive.”

“It is, isn’t it. I don’t know if you’ll be able to say anything about it to anyone or not, even in the hypothetical.” Alec sighs. “Mom’s the us. She’s.” Alec gestures down at his legs, and Magnus can’t help but wonder what Maryse’s tail looks like. Can’t help but wonder how much her hidden heritage had to do with how desperate she was to join the Circle, if she was trying to drive it out of _herself_ even more than the poor Downworlders she attacked. Magnus shakes his head. That’s for another time.

“The mer blood is in the Trueblood line,” Alec says. “But it doesn’t manifest for everyone, so Izzy and Max…”

“Don’t change, so they don’t know, so you can’t tell them.” Magnus finishes the sentence for him.

Alec nods. “Mom’s brother didn’t have it, or her dad, but her Grandfather did. Suppose we’re really lucky he lived long enough to explain it to her.”

“Does Robert know?”

“I never quite had the nerve to ask my mother that. I don’t think he does, though. You had to put it together, and I don’t. I don’t think it would have occurred to him to think that much about what makes Mom tick.”

Magnus squeezes Alec’s hand and shakes his head. There’s nothing that will make that better, especially since Magnus thinks Alec’s probably right. "Tell me about the curse.“

"When Adam Trueblood Ascended, he wouldn’t let his wife Mara attempt it. Which wasn’t that unusual at the time, women weren’t usually considered as potential soldiers, and as long as one parent was Nephilim their children would be too, so no one really cared. In fact, some people preferred it, considering the success rate, but either way, it was noted in the family history.”

Magnus feels a twist of something queasy in his gut. He has a sneaking suspicion this is not a pretty story. “But he had more reason than usual.”

“He didn’t know what it’d do to give the Cup to a mermaid. Especially one without her Heart.”

“Oh _demons,_ that’s horrifying.” Magnus has to close is eyes for a breath. He knows what that is, a mer’s Heart isn’t actually their _heart,_ it’s a scale. _The_ scale. He doesn’t know how to tell _which_ ; the question had always simply been an academic one, as he didn’t know there were still mermaids around anywhere. Plus it’s not as if he’d want to steal someone’s magical heart. It works like a selkie’s skin; without it they’re never whole, and they can’t return to themselves, trapped forever in a human skin.

Hearts are also used in a lot of dark magic. There’s an old myth that eating a mermaid’s heart grants immortality, and more than a few people had attempted to find some truth to that, back when mer were common, either magically or literally, with both the physical heart and the Heart-scale.

Alec makes a half-choked noise of agreement. “Their children thought so too, when they figured it out, but.”

Magnus definitely doesn’t want to know. “But?”

“When they tried to steal the Heart back to return it to their mother, Adam destroyed it.”

Magnus closes his eyes, but it doesn’t help. “What happened to Mara?”

“We’re not sure.” Alec’s hand slips free, his body shifts, and Magnus can hear the faint tink of Alec’s mug tapping against his table before his arms are back, settling around Magnus to keep him close. “There are a couple different theories. It might have killed her instantly, or her magic went wild and eventually she poured so much out she died, or perhaps she killed herself with it on purpose. The worst version is that it turned her feral, and her own children had to kill her.”

Magnus wraps himself around Alec as much as he can, pressed against his side, clinging to his chest. It’s horrifying on her behalf, of course, but Magnus can’t help but be much more afraid of such a thing happening to Alexander.

Alec kisses the top of Magnus’ head, and Magnus squeezes a little tighter before he manages to relax his grip a bit.

“Her children returned Mara to the sea. It was the only thing they thought they could do for her.”

Alec’s silent for a moment. Magnus waits. He’ll wait forever for Alec to find the words he needs, especially for this.

Especially after he almost didn’t wait, almost didn’t trust his Alexander.

 _“When sky meets sea, neither breathes_  
blood covers the land between  
too much, too soon,  
too little, too late

_Neither will ever be home again_

_Trueblood’s children share Mara’s fate_  
_caught between_  
love and lies, hope and rage  
_Voiceless, Heartless_ __  


_They will never have a home again”_

There was a lilt to Alec’s voice that Magnus had never heard before. Not just the studied edge of recitation, not just the rhythm of the words themselves, but the lift of tides, the weight of grief.

“The day after their mother died, after they returned her to the sea, Mara’s children woke up changed, with the sound of the ocean in their dreams.”

“And some of you still do.”

“And some of us still do,” Alec agrees. “Beyond that, we’ve lost most of the details. The first time we’re in saltwater we change, but after that it’s usually something we have control over, unless we’re very tired or have been away from water for too long.”

“That’s why today you couldn’t stop it.”

“Thankfully.” Alec kisses the top of Magnus’ head again, and Magnus turns to tuck his smile against Alec’s shoulder.

“I’m sorry I almost didn’t listen. I know you better than to think—”

“That I’d hide a gigantic personal secret from you?” Alec huffs out a breath, heavy enough Magnus can feel his hair move. “I couldn’t help it, but to be fair to yourself, you weren’t wrong.”

“You’ll have to tell me how much the books get wrong about the mer.”

Alec sighed. “Won’t be able to, I’m afraid.”

Magnus pulled back just far enough to look into Alec’s face. “Really?”

“ _Voiceless, Heartless._ ” Alec taps his chest, right above his heart. “I can feel the sea in here, can feel the tug towards other mer when I’m in the ocean, but I don’t know where they are, or how to find them. Even if I could, I couldn’t ask them anything, couldn’t tell them why I don’t know what I am.”

 _Oh._ Magnus’ mouth moves, but he can’t quite make a sound.

“I can feel the magic in me, but I can’t touch it.”

Magnus shudders, tries to imagine growing up with his father’s fire in his veins and no way to use it, no way to balance out the fear of the first time he saw his own true eyes with the singing of magic in his soul. “I’m so sorry, love.”

“Not your fault.”

Magnus rolls his eyes. _Never claimed it was._

“But thank you.” Alec’s hands are as warm as usual again as he cups Magnus’ jaw and pulls him in for a gentle kiss. “I’m so glad you know.”

Magnus hums, half appreciation, half agreement. “You’ll have to take me swimming some day, see if we can figure any of it out.”

Alec stills, eyes gone wide. “You think we can?”

“I doubt any of the other Trueblood children had a Warlock with a vested interest in teaching them magical theory.”

Alec’s startled expression softens into a warm smile. “I’m sure they didn’t. Poor them.”

Magnus grins back. “It’s always been assumed that the mer were closer to Seelie than Warlock in terms of magic and bloodlines, but no one knows for sure. Besides, a lot of the, hmm. Mechanics are similar, and I know a bit about how the Seelie do things.”

“Worth a try.” Alec kisses him again, leaning in even as he’s speaking, as if he can’t control himself, can’t stop himself, wouldn’t want to even if he could. “Plus, any excuse for a beach vacation?”

Magnus attempts to feign an innocent expression. “Would I need an excuse for a beach vacation?”

Alec snorts. “I suppose not.”

Whatever he was about to say next disappears into a gigantic yawn, and Magnus swallows a snicker. “Come on then, we’ll figure out logistics tomorrow.”

Alec hums in agreement, and tugs on Magnus’ shoulders until they’re both lying down properly, Alec’s head resting on Magnus’ chest much like he was in the tub. “M'so glad to be home.”

Magnus kisses the top of his head, and smiles into his hair. “So am I.”


End file.
